Aqueous dispersion adhesives are used widely, especially for the bonding of textiles.
For the bonding of films, more particularly decorative films, using dispersion adhesives, the films are typically pretreated with a primer. These primers are based in general on solvents and are therefore disadvantageous from the standpoints of occupational hygiene and safety. Also known are aqueous polyurethane primers which contain sulfonate groups. These primers, however, exhibit weaknesses under climatic and thermal loads, and therefore in many cases lead prematurely to failure of the adhesive bond.
Among aqueous dispersion adhesives a trend has been noted in recent times toward one-component aqueous dispersion adhesives. For instance WO 2005/113627 A1 discloses aqueous one-component dispersion adhesives which are based on a polyurethane containing carboxyl groups and carbodiimide groups or a polyurethane containing carboxyl groups and a carbodiimide.
It has emerged, however, that for these one-component dispersion adhesives as well the use of primers is an advantage. But the known primer systems exhibit the weaknesses mentioned above.